Trees, forests and water: Cool insights for a hot world

TLDR

Forest-driven water and energy cycles are poorly integrated into climate and land‑use decision‑making, limiting humanity’s ability to protect climate and life‑sustaining functions, yet research shows forests regulate carbon storage, cooling, and water distribution and must be prioritized in planning. The study calls for shifting from a carbon‑centric to a hydrologic and cooling‑centric paradigm, prioritizing trees and forests in climate and water planning. The authors review and analyze forest‑centric research to build a knowledge base that can inform better planning, policy, and action. Tree cover benefits climate at local to continental scales, and understanding its influence on water, energy, and carbon cycles informs planning, governance, and the use of forests for sustainability, adaptation, and mitigation.

Abstract

Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity’s ability to protect our planet’s climate and life-sustaining functions. The substantial body of research we review reveals that forest, water and energy interactions provide the foundations for carbon storage, for cooling terrestrial surfaces and for distributing water resources. Forests and trees must be recognized as prime regulators within the water, energy and carbon cycles. If these functions are ignored, planners will be unable to assess, adapt to or mitigate the impacts of changing land cover and climate. Our call to action targets a reversal of paradigms, from a carbon-centric model to one that treats the hydrologic and climate-cooling effects of trees and forests as the first order of priority. For reasons of sustainability, carbon storage must remain a secondary, though valuable, by-product. The effects of tree cover on climate at local, regional and continental scales offer benefits that demand wider recognition. The forest- and tree-centered research insights we review and analyze provide a knowledge-base for improving plans, policies and actions. Our understanding of how trees and forests influence water, energy and carbon cycles has important implications, both for the structure of planning, management and governance institutions, as well as for how trees and forests might be used to improve sustainability, adaptation and mitigation efforts.